Many studies have been conducted of high functional polymers that are capable of being applied to information and optical materials and catalysts used to produce the polymers. Novel transition metal catalysts have been studied to develop high-transparency and low-insulation cyclic olefin polymers (Makromol. Chem., Macromol. Symp., 1991, Vol. 47, 83; Angew. Makromol. Chem., 1994, Vol. 223, 121). Cyclic olefin polymers are produced using cyclic monomers such as norbornene and are applied to optical materials such as CDs, DVDs, and POFs (Plastic Optical Fiber), information electronic materials such as capacitor films and low dielectric materials, and medical materials such as low-absorption syringes and blister packaging due to excellent transparency, heat resistance, and resistance to chemicals, and very low birefringence and water absorption as compared to known olefin polymers.
Mitsui Chemistry, Co., Ltd., JSR, and Nippon Zeon, Co., Ltd. in Japan, Ticona, Co. in Germany, BFGoodrich, Co. in the United States and the like have commercialized cyclic olefin polymers such as PNB (Polynorbornene) and COC (Cyclic Olefin Copolymer) as high-transparency and low-insulation polymers late and applied them to information electronic, optical, and medical fields late in the year 1980s (U.S. Pat. No. 5,143,979; U.S. Pat. No. 5,191,026; Proceedings of MetCon'99 1999; EP Patent No. 156464; Modern Plastics, 1995, Vol. 72, 137; Proceedings of MetCon'98 1998).
The organometallic compound containing metal such as tungsten, molybdenum, ruthenium, nickel, and palladium is used as the reaction catalyst for cyclic olefin polymerization. The organometallic compound remains in the polymer after the polymerization reaction.
For example, U.S. Pat. No. 5,705,503 discloses ((Allyl)PdCl)2/AgSbF6 which is used as a catalyst to produce a norbornene polymer containing a polar functional group. In this connection, the amount of catalyst used is 1:100 to 1:250 based on monomers, which means that the catalyst is used in an excessive amount. Accordingly, catalyst residues remain in the resulting polymer in a large amount. Therefore, the polymer may deteriorate due to thermal oxidation and have reduced light transmittance.
Furthermore, Journal of American Chemical Society [J. Am. Chem. Soc. 1981, Vol. 103, 4627-4629] discloses polymerization of norbornene monomers having ester substituent groups using a cationic [Pd(CH3CN)4][BF4]2 catalyst. The polymerization has a low yield and exo isomers are selectively polymerized. Additionally, since the catalyst is used in an excessive amount of about 1/100 to 1/400 based on the monomer, there is a problem in that it is difficult to remove the catalyst residues after the polymerization.
The metallic catalyst compound remaining in the polymer generates a crack on the film during the production of the polymer film and reduces the transparency. Additionally, the high temperature is required to form polymer products. In this connection, since the polymer is discolored or decomposed at high temperatures due to the catalyst residue compounds, physical properties are significantly reduced. Therefore, a method for removing metallic compounds catalyst residue after the polymerization of the polymer has been suggested.
For example, U.S. Pat. No. 5,362,850 discloses a method for performing washing using alcohol in order to remove a catalyst which is contained in a polymer in an excessive amount when polyketone is produced using a palladium catalyst. However, the catalyst is inefficiently removed.
Furthermore, U.S. Pat. Nos. 5,231,164 and 5,750,772 disclose a method for using an inorganic filling material having a polar functional group. In the method, the inorganic filling material is added to the polymer solution so that the metallic catalyst compound contained in the polymer solution forms a chelate in conjunction with functional groups in the inorganic filling material, and only the inorganic filling material is filtered. In the method, it is easy to remove the metallic catalyst compound. However, the method cannot be used in practice due to the high-priced inorganic filling material having the polar functional group.
Additionally, Japanese Patent Application H 03-225290, and U.S. Pat. Nos. 5,462,995 and 5,990,246 disclose a method for removing catalyst residues from a polymer. Specifically, the polymer is a norbornene polymer, and it produced by performing ROMP (Ring Opening Metathesis Polymerization) using tungsten or ruthenium organometallic catalyst and then a hydrogenation reaction. In this case, the size of carrier of the heterogeneous catalyst used during the hydrogenation reaction may be controlled to remove catalyst residues from the polymer. However, the method for removing the catalyst residues is problematic in that it is difficult to control the removal of the catalyst residues and ensure commercialization.
Therefore, known technologies are problematic in that since high-priced inorganic filling materials are used or the removal effect of the catalyst residues is poor, processability is poor or it is difficult to ensure commercialization. Accordingly, there remains a need to develop a method for removing a high-quality optical polymer that is capable of avoiding the above-mentioned problems.